Wordpress: get posts and group by taxonomy terms.

group-posts-by-terms.php

/**
 * Get posts and group by taxonomy terms.
 * @param string  $posts Post type to get.
 * @param string  $terms Taxonomy to group by.
 * @param integer $count How many post to show per taxonomy term.
 */
function list_posts_by_term( $posts, $terms, $count = -1 ) {
	$tax_terms = get_terms( $terms, 'orderby=name');

	$args = array(
		'posts_per_page' => $count,
		$terms => $term->slug,
		'post_type' => $posts,
	);
	$tax_terms_posts = get_posts( $args );

	foreach ( $tax_terms as $term ) {
		echo '<h2>' . $term->name . '</h2> <ul>';
		foreach ( $tax_terms_posts as $post ) {
			echo '<li><a href="' . get_permalink( $post->ID ) . '">' . $post->post_title . '</a></li>';
		}
		echo '</ul>';
	}

	wp_reset_postdata();

}

nice and useful/ thanks